Stereochemical Effects on the Physical Properties of Polymers | CHEM 343, Lab Reports of Chemistry

Download Stereochemical Effects on the Physical Properties of Polymers | CHEM 343 and more Lab Reports Chemistry in PDF only on Docsity! Stereochemical
Effects
on
the
Physical
Properties
of
Polymers
 Prelab
Questions:
 Reading
Materials:

Chapter
22
in
the
book
has
some
basic
information
on
polymers.

In
 addition,
a
wikipedia
search
of
“polymers”
will
bring
up
important
information
to
complete
 the
prelab
questions.

Any
general
textbook
on
polymers,
such
as
would
be
found
in
the
 library,
will
also
have
answers
to
these
questions.

The
experimental
procedures
may
also
 provide
some
useful
information.


 1.
Provide
an
arrow
pushing
mechanism
for
the
thermal
decomposition
of
initiator
2,2’‐ azo‐bis‐isobutyronitrile
(AIBN).

(2
pts)
 
 
 2.
Assign
the
diad
tacticity
for
the
following
polymer
sequence
(e.g.
m
or
r
for
each
diad).

(2
 pts)
 
 
 3.
What
is
the
difference
between
number
average
(Mn)
and
weight
average
(Mw)
 molecular
weights?

(2
pts)
 
 4.
What
is
the
primary
information
that
we
get
from
differential
scanning
calorimetry
 (DSC)
for
PMMA.

(2
pts)
 
 5.
Why
was
xylene
used
as
the
solvent
rather
than
toluene
for
the
reaction
at
138
oC
?








 (2
pts)
 
 Report
Questions:
 1.
Given
the
following
1H
NMR,
calculate
the
mole
fraction
of
the
mr
diad.

(2
pts)
 N N CN NC AIBN